I've got a misfire in my #3 cylinder at about 75mph with light throttle. Runs fine everywhere else. Changed the spark plug, no change, changed the plug wire, which turned out the boot was split and the last mechanic taped it up with electrical tape. Thought it was solved but no. Swapped injectors and misfire is still on #3. Disconnected the Crane ignition box, still misfiring. Checked the compression and is reading 130psi, which matches cylinder one (only checked those two) with trickflow 62cc heads and a Vortech S-trim supercharger. I'm figuring it's a bad pickup in the rotor/cap portion of the optispark, but wanted to see if I left anything else out before I spent the money on one.

 

Check the plug wire again before replacing the opti.

 

I double checked it and it looks fine. I thought maybe some contaminants could have found there way into the distributor portion of the opti with the split boot, but the connector was clean. I guess I'll order a new opti.

 

You said you swapped injectors but did you check to see if the clip is getting pulses from the PCM?

 

If the injector was failing to get a pulse, would it not throw a corresponding code? The plug that came out of #3 was very black and sooty, so hopefully that means the injector is firing okay? It runs just fine at idle, cruising around town and at WOT. It's just when I get on the highway that it starts misfiring, and I can clear it up with a blip of the throttle/change in rpm.